Generating a wavelet dictionary for sparse representation of images

Hello,

I am trying to represent the patches of an image in terms of the wavelet basis/columns of a dictionary/sensing matrix using the relation y = Ax where y is a patch, A is the dictionary and x is the sparse vector. How do I generate this dictionary in MATLAB containing only wavelet basis. The size of the patch 'y' in vector form is lets say 25x1. Please help.

Thanks in advance.